. He was reading his book, completely _______ to the world.
Every exercise ______ on a different grammar point. You should go over the main points of the grammar rules related before you work each of them out.
The teacher______have thought Johnson was worth it or she wouldn't have wasted time on him,l suppose.
Eventually, he admitted ______ the diamond necklace.
Before the writer gave her first performance,her______very fast.
---This book by Tony Garrison is of great use for our course.---But I think his latest one is______ worth reading.